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101.
溶胶-凝胶法制备BaTiO3纳米粉体 总被引:4,自引:0,他引:4
阐述了用溶胶-凝胶工艺的半醇盐法制备BaTiO3纳米粉体的基本原理和工艺流程,讨论了溶剂、pH值、Ti/Ba摩尔比以及热处理工艺对BaTiO3纳米粉体性能的影响,并分析了目前以该法制备BaTiO3纳米粉体存在的问题。 相似文献
102.
U. Vijayalakshmi M. Chellappa U. Anjaneyulu Geetha Manivasagam Swaminathan Sethu 《Materials and Manufacturing Processes》2016,31(1):95-106
The purpose of this study is to synthesize and characterize nanosized titania (TiO2), zinc oxide (ZnO), and its composite coating on Ti–6Al–4V to enhance its corrosion protection behavior in Ringer's solution. Nanosized powders of TiO2 and ZnO was characterized by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), and scanning electron microscopy - energy dispersive atomic spectroscopy (SEM-EDAX) analysis. As a result of antibacterial activity, both ZnO and TiO2/ZnO have produce remarkable inhibition zone on Escherichia coli. The antibacterial activity of composites are due to the combined effect of ZnO on TiO2. The adherence and surface uniformity of TiO2/ZnO composite film on titanium implant was examined by optical microscopy and Vickers microhardness test. Corrosion resistant behavior of the coating on titanium implant was investigated by tafel polarization and impedance analysis. The composite coatings on Ti–6Al–4V have produced improved corrosion resistance with a pronounced shift in the anodic corrosion potential (Ecorr) with a corresponding less corrosion current density (Icorr) compared to monophase coating. Similar results have been obtained for impedance analysis which indicated a reduction in double layer capacitance (Cdl) and with enhancement in charge transfer resistance (Rct). These observations suggest improved corrosion resistance property of TiO2/ZnO composite coating on Ti–6Al–4V. 相似文献
103.
104.
高度取向ZnO薄膜的介电和光波导特性研究 总被引:4,自引:0,他引:4
用溶胶凝胶法在不同的基片上制备了具有高度 c 轴即(002)取向的 Zn O 薄膜,研究了溶剂、稳定剂等对合成的先体溶液的影响。对薄膜的 X R D 分析表明随热处理温度的增加,c 轴取向度增大,并且薄膜的晶粒尺寸在 300 ° C~500 ° C 范围内增幅较大。用端面耦合的方法测量了制备在 Si O2/ Si(111)基片上薄膜的波导损耗,即随热处理温度的增加,波导损耗增大,主要来源于 Zn O 薄膜与 Si O2 的界面及晶粒的散射。制备在 Pt/ Si O2/ Si(111)基片上薄膜的相对介电常数为 7~13,电阻率则为 1.7×104 Ω·cm ~9.8×105 Ω·cm 。 相似文献
105.
Julien Chauvet 《Polymer》2005,46(23):9555-9561
Poly n-butylacrylate latexes are commonly used as the base ingredient in the formulation of pressure sensitive adhesives, PSA. In the typical starved semi-batch process carried out to produce this latex and due to the non-linear nature of the kinetics, chain transfer to polymer plus bimolecular termination by combination, polymer networks are produced. The molar mass distribution of these polymer latexes is characterized by a soluble and an insoluble fraction, so-called gel. Both fractions strongly affect the adhesion properties, but unfortunately the independent control of these properties is a difficult task, that has not been solved yet. In this work, the concentrations of chain transfer agent and cross-linker were used in an attempt to exercise control over the molar mass of the soluble part and the amount of gel polymer. It was found that by simultaneously manipulating both variables it was possible to modify the gel content of the polymer without completely sacrificing the sol molar mass. The adhesion properties, tack and resistance to shear, measured on films cast from the latex demonstrated that a good PSA can be obtained by properly balancing the amount of CTA and cross-linker in the formulation. 相似文献
106.
Transparent conducting SnO2 powders doped with 10% Fe content were prepared by a polymerized complex method under acidic solutions, and annealed finally at 550 °C, and at 600 °C. These samples were characterized by X-ray diffraction, magnetization, and Mössbauer spectrometry at room temperature. Rutile SnO2 phase was obtained for both samples, and the crystallite sizes were in the range of 13-14 nm. Both samples exhibit magnetization and the saturation magnetization was smaller for the sample annealed at 600 °C than for sample annealed at 550 °C. Room temperature Mössbauer spectra for both samples showed the presence of two different paramagnetic iron sites but no magnetic sextets. These results suggest that ferromagnetism originates from magnetic defects and not directly from iron ions. 相似文献
107.
108.
Federico González María-Elena Villafuerte-Castrejón Alfonso Huanosta 《Journal of Electroceramics》2007,18(3-4):323-327
A Pb0.98Eu0.02(ZryTi1−y
)0.995O3 compound series, with y = 0.60, 0.53 and 0.45 was prepared. PZT samples were synthesized by sol–gel technique. The crystallization and quality of
the compounds were analyzed by powder X-ray diffraction and electron microscopy. The shape of the ε′(ω) vs T curves can be considered typical of a ferro-paraelectric transition. The ferro-paraelectric transition temperature
for each composition was 348, 328 and 307°C, for the y = 0.45, 0.53 and 0.60, respectively. σ′(ω) is strongly influenced by short range processes. For the logσ′(ω) curves as function of temperature, there is evidence of a non dispersive dc-conductivity component for the high temperature
region. The associated dc-activation energies are larger than those calculated for the ac region (at lower temperatures). 相似文献
109.
以无机盐和金属醇盐为前驱物 ,用溶胶 凝胶法制备了超细Li2 xSmxSi1-xO3(x =0~ 0 0 9) ,用DTA、XRD、TEM及交流阻抗等技术对样品的结构、形貌、粒径及离子导电性等进行了观察和测试。其固溶体形成范围是 0 相似文献
110.
Modelling and simulation results for a domestic exhaust-air heat pump heating system 总被引:1,自引:0,他引:1
Energy consumption in residential buildings has gained an increasing interest the latest years due to the rising demand for efficient energy use and higher comfort standards. In tight building constructions with controlled ventilation, heat recovery with exhaust-air heat pump connected to floor heating is regarded as energy efficient heating system that optimises the energy use in buildings while maintaining an acceptable level of thermal comfort. In this study, we use the computational tools TRNSYS and EES to model and analyse the performance of a residential house, its ventilation system and its floor heating system based on an exhaust air heat pump. The system analysis focuses particularly on the influence of internal and solar gains on the operation of the heating system and the thermal comfort of the house. Furthermore, the way that gains influences the performance of the floor heating system is examined. Overall, the results bring to light the impact of factors that are not easy to predict on the indoor climate and the thermal comfort. 相似文献